Priming mixture



Patented June 11, 1935 This invention rel'ates' ts improvements in: pr ming mixtures for small arms ammunition, and 'more' particularly 'to priming mixtures in' which the oxidizing' agents are o'f a non-wrrosive type Itis one of the objects'of the pres"- ent:inven'tion to provide apriming mixture having an initiator, a sensitiz'er, a'fuel ingredient, and an oxidizing ingredient, none of which will produce a corrosive residue in the g'unl- It is a-lfurther' object' of the presentinventionto avoid the use of mercury fulminate. To attain these and other objects I employ an initiat0l,i00IlSiStiIlg 0f normal lead azide, a-sensitizer, as hereinafter defined more at length, afuel' in-' gredient preferably consisting of antimony sul- 1 phide, 'lea'd sulphocyanide 'and cal'cium' silicide,

or their equivalents; and an oxidizing ingredient preferably consisting of lead' peroxide" and barium nitrate, :ortheir'equivalents, either with Y or without minor additions of components here'- tofore used in priming compounds to control or vary thezicharacteris'tics thereof :5.Heretofore.mercury =fulmina'te hasbeen' generally used as the initiator in priming mixtures "for smallarms ammunition. It possesses many composition of the mercury fulminate when the cartridge is exploded prevents reloading of center fire cartridges. By employing an initiator in which no mercury fulminate is present, this amalgamation is eliminated, which permits reloading and re-use of center fire cartridge cases. The priming mixture of my invention also possesses advantage for use in rim fire primers. It has greater stability on storing and therefore permits the ammunition to be used and better results obtained after it has been stored forlong periods of time. A suitable priming mixture for center fire cartridges may be formed by mixing the following ingredients in substantially the following proportions, by weight:

Tetrazene 1 to 5% preferably 3% Normal lead azide to 20% preferably 12% Barium nitrate 1 20 to 30% preferably 23% Lead peroxide to 25% preferably ,qJosephlD McNutt,-,l lew (lo nu v1. 1:0Hillinche ster RepeatingArms. Company, New- ,Ha-vemfionm, a, corporation of -Maryland;

N6 Application Augusttil, 1932 assignor Serial No. 531,102

(dye-4 t k Antimony sulphide' 15m preferably 20% Calcium silicide 5 to"-15% preferably 10% lie'ad -sulphocyahide 10 to20% preferably 12% Proportions of thes'e ingredients may be varied depending onithestr ength or purity of the ingredients; as, obtainable commercially. Also the proportions maybe varied to'correlate the characteristics of the priming mixture to the size of thefl'art. I

he terms.tetrazene and ftetrazole derivatives have been 'variously defined by earlier workers in the'explosives art and there is much confusion in nomenclature; Likewise, structural formulae for these materials as heretofore published arenot easily reconcilable. The material whichll employ may be obtained by treating aminoguan'idine in the form I of its bicarbonate saltto convert it to the sulphate or soluble form of that salti- Thus the dry bicarbonate is treat- 2 ed with a slight excess of 6% sulphuric acid. To a 15% water solution of this sulphate of aminoguanidine, while still acid from the excess of sulphuric acid, I add a aqueous solution of sodium nitrite and allow the two solutions to react at a temperature between 30 and C. for a period of 1 to 2 hours, when the reaction is complete. The solid residue is then washed with water and then with alcohol and dried at room temperature, or somewhat higher, from 5 to 10 hours, depending on operating conditions. The chemical structure of the resultant product is complex. Throughout this specification I designate it as tetrazene. The material is apparently one species of the generic class of compounds sometimes called tetrazenes and has been designated by the term guanylnitroso-aminoguanyltetrazene. Thus in French Patent No. 671,800 to Rathsburg et all, dated September 9, 1929, the name tetrazene is used as synonymous with guanylnitroso amino guanyltetrazene, though it must be recognized that tetrazene is the genus of which the alleged synonym is but one of scores of species.

To make primers from the ingredients above tabulated, these ingredients are first thoroughly and homogeneously mixed. The mixture is then poured into individual pellets of the proper size for the individual charges, all in a customcartridge, the magnitude of the gun powder 0 aryway.

The priming mixture forming the subject matter o? the present ginvefi'tion'; may fals'o be employed in rim fire cartridges and Without substantial change in the illustrative proportions above set forth, excepting for the addition of say 20% of ground glass, the latter being -a common constituent of rim fire mixtureswhere'" serves as an abrasive in :a manner WeIl un derstood in the art. Withrlm 'firelmi-xtures'as in the relative percentages of theinitiator, the sensitizer, the oxidizer, and the fuel, to correlate the priming mixture to the size of the shelland to the nature and amount of powder usedthereof a charge plate and then transferred to empty rim fire cartridge shells. The priming mixture then fl-creed to distributeitselfintofihe'ihollow rim of "the cartri'dge'shell byfspinr'iing'the shell in the customary machine. The shells are then loaded with powder and "bullets in'the 'custor'n- The "oxygen supplying elements and fills mentioned above? are referred to; ample?Knownequivalentsmay ,7 I foranyor all of them without departingfrom the spirit crthe'invention. Asan examplejle'a'd nitrate may be .employedin place ,.of bariumjnltrata'the quantity of'lead nitrateto be employed varying slightly "from 'the'i quantity o fjfbarium nitrate given above .to obtainsubstantially the same qualitiesinthe resulting mixture.

I claim:

1. A priming "for small arms ammu nition, comprisingnormal lead 'az'i'de, suitable oxidizers and 'fuels and tetra'zene. 3

' nitresa mi u l 'W YQ IQ X-Yi substituted tion comprising normal lead azide, barium ni trate, lead peroxide and tetrazen 3. A priming mixture for small arms ammunition comprising normal lead azide, barium nitrate, lead peroxide, calcium silicide, antimony sulphide and tetrazene.

l. A priming mixture for small arms ammunitidn comprisingfwrmalflead azide; tetrazene, barium nitrate; lead peroxide, antimony sulphide, calcium silicide and lead sulphocyanide. 5. A priming mixture for small arms ammuniti-omeornprising 10% to 20% normal lead azide, 20% to30'% barium nitrate, 15% to lead perox-lde, "ll5% ito25% antimony sulphide, 5%

I I 'to 15% 'calciumsilicide, 10% to 20% lead sulwith center fire mixtures, changesma'ybe'made' -niti'on- -consisting essentially of about 12% normal lead azide, 3% tetrazene, 23% barium nitrate,20%'- lead peroxide, 20% antimony sulphide =calcium.;,silicide and .-12.% lead sulh cramd y, a J. A priming-mixture=for small arms ammunition consisting essentially of normalxleadazide, tetraaene, barium nitrate, lead peroxide, antimony sulphide, calcium, silicide, lead sulphocyanide; andzground glass. l; ,7 :8, All "improved 1D. H vg, Emixture ,ifor :small arms ammunitioncccmprising lead'azide, guanylnoguanyltetrazene,ibarium nitrateiand .9, ;;imp ;oyed-, priming, mixture 'forxsmall rm ammu ti n comprisin -l ad azidet euanr v nitrosoaminoguanyltetrazene, ,.;:barium'..,.nitrat.e, and ;calciumz si-lieide. -1, z

.;10 :-A :pri-mingmixture, "or ammunition primers comprising -gguanylnitrosoaminoguanyltetrazenej and-leadzazida- 1.;An pproyed-primingicomposition roomprising ,leadrazide,1guanylnitrosoaminoguanyltetrazene, g-barium mitrateiandi-a :fuel in which the lead azide contentzisefromiltlitoizll:pereent andv the,guanylnitrosoaminoguanyltetrazenecontentis from]; pr ming'mixtureforsmall ar f 

